Pyridazino[1, 2-a]-pyridazine-1, 4-diones and pyridazino[1, 2-b]-phthalazine-6, 11-diones



rates 3,062,820 Patented Nov. 6, 1962 3,062,820 PYRIDAZINO[1,2-a]-PYRlDAZINE-1,4-DIONES AND PYRIDAZINO{1,2-h]-PHTHALAZINE-6,1l-DiONES Thomas J. Kealy, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL,

a corporation of Delaware No Drawing. Filed May 2, 1960, Ser. No. 25,883 8 Ciaims. (Cl. 260-250) This invention relates to new nitrogen heterocyclics. More particularly, it relates to new pyridazine derivatives and methods of preparing them.

The new products made available by this invention are the 1,2-maleyl-l,2,3,6-tetrahydropyridazines and the 1,2- phthaloyl-1,2,3,6-tetrahydropyridazines represented generically by the formula in which case the compound is a 1,2-phthaloyl-1,2,3,6-tetrahydropyridazine. The symbols R through R represent hydrogen or alkyl radicals, and R and R together can form an alkylene bridge joining the carbon atoms in the 3- and 6-positions in the pyridazine ring. Thus, the

compounds of this invention correspond to one of the formulas (I) 0 R1 R2 with the proviso that R and R can form an alkylene bridge, in which case the pyridazine ring in the above formulas has the structure 5 yea...

where Q is a divalent alkylene radical.

'In accordance with the rules of nomenclature followed by Chemical Abstracts, the compounds of Formula I may be named 6,9-dihydropyridazino[l,2-a]pyridazine-l,4-diones, and those of Formula II l,4-dihydropyridazino[1,2- b]phthalazine 6,11 diones'. However, the somewhat shorter names 1,2-maleyland 1,2-phthaloyl-1,2,3,6-tetrahydropyridazines will be generally used throughout this discussion for the sake of brevity.

The compounds of this invention are prepared by bringing in contact an aliphatic or cycloaliphatic 1,3-diene hydrocarbon, i.e., an aliphatic or cycloaliphatic hydrocarbon containing a conjugated system of double bonds, with pyridazine-3,6-dione or phthalazine-L4-dione, in a liquid organic solvent and at temperatures, below about 0 C., where the heterocyclic reactant is stable.

The reaction that takes place is a Diels-Alder type condensation whereby the dienophile, that is, pyridazine-3,6- dione or phthalazine-1,4-dione, adds through its nitrogen atoms to the conjugated system of the diene at the 1- and 4-positions of the latter. It is represented by the follow- Equations 1 (with pyridazine-3,6-dione) and 2 (with phthalazine-l,4-dione), in which equations the symbols R -R have the previously stated significance and R and R together can be a divalent alkylene radical uniting the carbon atoms to which they are attached:

One of the starting materials used in this process is an aliphatic or cycloaliphatic 1,3-diene hydrocarbon. Compounds of this type are well-known[ They are either available commercially or obtainable by well established methods. The most accessible, and therefore preferred diene hydrocarbons for use in the process of this invention are those having from 4 to 16 carbon atoms, i.e., those in which the groups R to R when they are not hydrogen, are alkyl radicals containing together a total of 1 to 12 carbon atoms, with the proviso that R; and R together can be an alkylene radical, preferably containing from 1 to 5 carbon atoms.

The other starting material can be termed a 2,3-diaza' quinone and is represented by the formula (III) wherein R and R are hydrogen and when taken together R and R can form the divalent radical Thus, this starting material is either pyridazine-3,6-

dione,

These compounds, which may also be called, respectively, 2,3-diaza-1,4-benzoquinone where alk. stands for an alkyl radical (it is immaterial from the standpoint of this equation whether the maleic j hydrazide sodium salt is present as the N-salt, as shown,

or as its tautomer, the O-salt).

In this method, which is illustrated in greater detail in some of the examples which follow, an alkali metal salt, e.g., the sodium or the potassium salt, or another soluble salt, of the hydrazide can be used. These salts can be prepared by known methods. There can be used any Lalkyl hypochlorite, preferably one in which the'alkyl radical has from 1 to 6 carbon atoms, e.g., methyl, ethyl, n-hexyl hypochlorite. The preferred oxidizing agent, because it can be handled more safely, is tert.-butyl hypochlorite.

The two reactants are mixed, preferably in approximately equimolar proportions, in an inert organic liquid which is a solvent for the alkyl hypochlorite and for the reaction product and which, of course, is substantially non-reactive or inert toward the reactants and reaction product, though normally such inertness poses no problem in this process. As a solvent, there can be used any organic compound, free of aliphatic carbon-to-carbon unsaturation, which remains liquid at the low temperatures used and which dissolves both reactants at least to some extent, e.g., 0.1% by weight, at such temperatures. While it is true that such inert organic solvents are not available in great variety, in general they are readily available. Suitable solvents include dialkyl ketones and dialkyl ethers wherein each alkyl group contains up to 4 carbon atoms,

for example, acetone, methyl ethyl ketone, dimethyl ether, etc., and also cyclic ethers such as tetrahydrofuran or the like. Mixtures of these solvents can be employed.

Pyridazine-1,3-dione and phthalazine-l,4-dione are extremely reactive materials which lose nitrogen readily even at low temperatures. For this reason, their preparation is conducted at temperatures where they are stable in solution. It is recommended that reaction temperatures not exceed about 0 C., and the oxidation is preferably carried out below about -40 C., especially when py- -ridazine-3,6-dione is being prepared. A convenient temperature range is that between about and 50 C., although temperatures below -80" C. can be used with low freezing solvents. Temperatures down to the freezing point of the solvent medium can be used.

Phthalazine-l,4-dione can be isolated as a solid and it is stable at ordinary temperature for limited periods. Pyridazine-3,6-dione can also be precipitated as a solid from its solutions, but it is stable only at low temperatures. Both products are best stored and handled in solution at temperatures below about 40 C.

The synthesis of the 1,2-maleylor 1,2-phthaloyl-l,2, 3,6-tetrahydropyridazines is conducted simply by bringing the appropriate 1,3-diene (described above) into contact with the appropriate 2,3-diazaquinone (described above) in an inert liquid organic solvent at temperatures below about 0 C. and preferably below 40 C., especially when using pyridazine-3,6-dione. A convenient temperature range is that between -80 and S0 C., although lower temperatures, e.g., as low as -lO0 C., can be used. Temperatures down to the freezing point of the solvent can be used.

The reaction is essentially instantaneous even at the low temperatures involved. Its progress can be readily followed by observing the disappearance of the green color characteristic of either of the heterocyclic starting materials.

The reactants are mixed, preferably in about equimolar proportions, in an inert organic compound which is liquid at reaction temperature, is at least a partial solvent for the reactants, and is preferably one in which they are soluble at least to the extent of 0.1% by weight at reaction temperature. The solvent should, of course, be substantially inert or non-reactive towards the reactants. Inertness towards pyridazine-3,6-dione or phthalazine-l,4-dione is readily determined by the absence of change in the already mentioned green color of these products. Inertness towards the diene reactant is normally no problem, especially at the low temperatures involved. Suitable inert liquid organic solvents include those already mentioned above in connection with the preparation of the starting materials.

In a preferred mode of practicing the process of this invention, the pyridazine-3,6-dione or phthalazine-1,4-dione is not isolated from the solvent in which it was formed, but the reaction mixture (preferably after removal of the alkali metal chloride and other insoluble materials by filtration) is instead treated directly with the 1,3-diene reactant.

The reactant proportions are not critical. In order to insure maximum utilization of the more expensive heterocyclic reactant, it is generally preferred to use the 1,3- diene reactant in at least equimolar amount with respect thereto, but this is not essential.

As already mentioned, the reaction is very rapid. The

reaction product, i.e., the 1,2-maleylor l,2-phthaloyl- 1,2,3,6-tetrahydropyridazine, often precipitates out of the reaction medium and can be separated by filtration. If this does not take place, the reaction product can be isolated by concentrating the solution or completely removing the solvent, or by adding a non-solvent to the reaction mixture. The reaction products are solids which, if necessary, can be purified by recrystallization from appropriate solvents.

The products of this invention (i.e., the compounds of Formulas I and II above) are useful as plant growth regulants, and particularly as control agents for noxious weeds. The compounds of Formula III are useful as intermediates in the preparation of these products.

The invention is illustrated in greater detail in the following examples. Y

Example I To a stirred solution of 5.4 g. (0.05 mole) of tertbutyl hypochlorite in 100 ml. of acetone at 80 C. was added 6.7 g. (0.05 mole) of the monosodium salt of maleic hydrazide. The temperature of the reaction mixture was then maintained at 55 to 65 C. for 3 hours, during which time the mixture developed a green color and the quantity of insoluble material decreased. The reaction mixture was then filtered through a cold sintered glass Buchner funnel under an atmosphere of nitrogen to obtain 3.3 g. of sodium chloride and unreacted material and a green filtrate containing the pyridazine-3,6-dione in solution. The product was precipitated from its solution as a light-green solid by addition of 200 m1. of cold chloroform to the filtrate at 80 C. Attempts to isolate it from its solution resulted, however, in sudden decomposition of the solid as it warmed up to room temperature.

, Inthis process, the potassium salt of maleic hydrazide can be used instead of the sodium salt. In fact, the potassium salt is preferred since it is more soluble in acetone and gives better conversions to pyridazine-3,6-dione at '80 C., which is a convenient operating temperature (that of solid carbon dioxide).

Pyridazine-3,6-dione is stable in solution at temperatures up to about 40 C., and such solutions were used in the condensations with dienes described in the examples which follow. When a solution of pyridazine-3,6-dione, obtained as described above, was allowed to warm up to room temperature, it was converted to an orange solution containing some undissolved white solid. The solid was removed by filtration and the filtrate was reduced in volume on a steam bath and cooled to obtain a yellow solid. Recrystallization of this solid from acetone atforded bright yellow needles, M.P. 247 C. (dec. block). In acapillary tube, the solid appeared to decompose slowly above 160 C. Elemental analysis indicated that this product was 1,4,6,9-tetraketopyridazino[1,2-a]pyridazine,

formed by condensation of two molecules of pyridazine- 3,6-dio'ne with loss of nitrogen.

Analysis.Calcd for C H N O C, 50.01; H, 2.10; N, 14.58. Found: C, 50.18; H, 2.32; N, 14.16 (Dumas). The structure of this compound was confirmed by treatment with-boiling water, which hydrolyzes it rapidly to maleic hydrazide and maleic acid.

Example 11 To a stirred solution of 5.4 g. (0.05 mole) of tert.- butyl hypochlorite in 80 ml. of acetone at 80 C. was added 9.2 g. (0.05 mole) of the monosodium salt of phthalic hydrazide. The solution was maintained near -80 C. for 3.5 hours, resulting in the formation of a deep-green color as the quantity of undissolved solid lessened. The reaction mixture was filtered free of solid, and to the green filtrate at -80 C. was added 150 ml. of coldchloroform, causing precipitation of a green solid. The suspension was filtered cold and the product was air-dried to obtain 1.5 g. of a product which was shown by elemental analysis to be phthalazine-1,4-dione.

Ana'lysis.-C-alcd for C H NgO C, 60.00; H, 2.52. Found: C, 60.28; H, 2.74.

Phthalazine-1,4-dione is stable at room temperature, at least for short periods. On longer standing, it slowly loses its green color with the formation of a white solid and a change in crystallinity. However, in some cases, the product decomposed exothermically on standing in air with a puff of white smoke, but with no flame or eX- plosion. In a melting point capillary tube, phthalazine- 1,4-dione loses its green color at about C. with no other noticeable change. It then decomposes with gas evolution at about 140 C. For reactions with dienes, the solution in which phthalazine-1,4-dione was prepared is preferably used directly. If desired, however, the solid can be isolated and redissolved in a solvent for the diene.

The above-described preparative procedure can be carried out at higher temperatures, e.g. up to about 0 C., although preferably not exceeding -40 C. The acetone can be replaced by another solvent, such as, for example, dimethyl ether which, because of its low boiling point, is convenient to use when it is desired to isolate the phthalazine-l,4-dione. In such a case the dimethyl ether can be removed very easily at -80 C. under vacuum to leave a mixture of the phthalazine-1,4-dione and tert.-butyl alcohol, from which the product can be precipitated by addition of a non-solvent such as chloroform, trichloroethylene or methylene chloride.

Example III To a stirred solution of 3.8 g. (0.035 mole) of tert.- butyl hypochlorite in 50 ml. of acetone at 80 C. was added 4.7 g. (0.035 mole) of the monosodium salt of maleic hydrazide. The reaction mixture was maintained at 60 to 70 C for 4 hours and then filtered cold to remove 2.1 g. of insoluble solid. To the green filtrate containing the pyridazine-3,6-dione thus formed was added at -80 C. 2.8 g. (0.35 mole) of 2,3-dimethy11,3-butadiene dissolved in cold acetone, causing the immediate discharge of the green color and the precipitation of a white solid (2.8 g.), M.P. 148.5l55 C. (dec.). Recrystallization of the product from acetone afforded large yellow needles, M.P. 153-159 C. (capillary tube) and 161 C. (block). This product was 1,2-rnaleyl-4,5-dimethyl-1,2,3,6-tetrahydropyridazine, which may also be named 7,8-dimethy1-6,9-dihydropyridazino 1,2-a] pyridazine-1,4-dione,

Analysis.Calcd for c d-1 N 0 C, 62.48; H, 6.29; N, 14.58. Found: C, 62.02; H, 6.26; N, 14.43 (Dumas).

The structure of the product was confirmed by its infrared and nuclear magnetic resonance spectra.

Example IV Pyridazine-3,6-dione was prepared as in Example III from 0.1 mole of tert.-butyl hypochlorite and 0.1 mole of maleic hydrazide monosodium salt in acetone. After removing the insoluble material by filtration, gaseous 1,3- butadiene' was passed into the green filtrate at 80 C., causing the discharge of the green color and the formation ofa lightly colored purple-pink precipitate. The suspension was filtered cold to obtain 9.5 g. of pale yell-ow solid, M.P. 154-158 C. Upon recrystallization from benzene or petroleum naphtha (B.P. -140 C.), the product showed constant melting point of 157-159 C. spectra showed that it was 1,2-1naleyl-1,2,3,6-tetrahydro- Its elemental composition and infrared and n-ni-r' 7 pyridazine, also named 6,9-dihydropyridazino[1,2-a]pyridazine-1,4-dione,

Analysis.Calc'd for C H N O C, 58.53; H, 4.91; N, 17.07. Found: C, 58.45; H, 5.38; N, 16.84 (Dumas).

This structure was further confirmed by catalytic hydrogenation over platinum oxide, which yielded 1,2-succinylhexahydropyridazine, M.P. 174-177 C. This product was found, by comparison of melting points and infrared spectra, to be identical with that obtained by reaction of succinhydrazide with 1,4-dibromobutane.

Example V Pyridazine-3,6dione was prepared as in Example III from 0.05 mole each of tert.-butyl hypochlorite and the sodium salt of maleic hydrazide in acetone. The reaction mixture was filtered at 80 C. and to the cold filtrate was added a solution of 3.3 g. (0.05 mole) of cyclopentadiene in 20 ml. of acetone pre-cooled to 80 C. The green color was discharged instantaneously to give a yellow solution which, on standing 2 hours at 80 C., deposited 4.0 g. of pale yellow solid, M.P. 157- 160 C. This product was very soluble in cold chloroform. It was recrystallized from a chloroform-petroleum naphtha mixture to a constant melting point of 178- 181 C. Elemental and infrared analyses showed that this product was 1,2-maleyl-3,6-methano-1,2,3,6-tetrahydropyridazine, which may also be named 6,9-methano- 6,9-dihydropyridazino[1,2-a]pyridazine-1,4-dione,

Analysis.-Calcd for C H N O C, 61.36; H, 4.58; N, 15.90. Found: C, 61.46; H, 5.01; N, 15.83.

This product is prepared in better yields when the first step of the reaction is carried out by oxidation of the potassium salt of maleic hydrazide with tert.-butyl hypochlorite in acetone at 80 C. for 1.5 hours and when the cyclopentadiene adduct is recrystallized from a cholorform-acetone mixture.

Example VI Pyridazine-3,6-dione was prepared by the reaction of 7.5 g. (approximately 0.042 mole; 85% pure) of the potassium salt of maleic hydrazide with 5.4 g. (0.05 mole) of tert.-butyl hypochlorite in 125 ml. of acetone at 80 C. for 2.5 hours. The reaction mixture was filtered, and to the filtrate at 80 C. was added a cold solution of 4.5 g. of 1,3-cyclohexadiene (83% purity) in 20 ml. of acetone. Some solid separated immediately. After the reaction mixture had been allowed to stand for about 16 hours at a temperature well below C., it was filtered to obtain 4.84 g. of pale yellow crystals, M.P. 198-205 C. This product was recrystallized from benzene to a constant melting point of 212-2l4.5 C. Elemental and infrared analyses showed that it was 1,2- maleyI-3,6-ethano 1,2,3,6 tetrahydropyridazine, also 8 named 6,9-ethane 6,9 dihydropyridazino[1,2-a]pyridazine-1,4-dione,

Analysis.--Caled for C H N O C, 63.15; H, 5.30; N, 14.73. Found: C, 63.59; H, 5.36; N, 14.87.

Example VII Phtl1alazine-l,4-dione was prepared as described in Example II from the reaction of 9.2 g. (0.05 mole) of phthalic hydrazide monosodium salt with 6 g. (0.0555 mole) of tert.-butyl hypochlorite in 150 ml. of acetone. To approximately one-half of the filtrate from this reaction was added a solution of 2.1 g. (0.025 mole) of 2,3- dimethyl-1,3-butadiene in acetone at C. The green color of the phthalazine-1,4-dione solution was immediately discharged and a tan solid separated, 2.9 g. On standing overnight under a watch glass, the tan solid developed a yellow color. Recrystallization of this solid from acetone afforded 2.0 g. of a mixture of almost colorless prisms (A), M.P. 198 C. (block) and long yellow needles (B) having the same melting point. Concentration of the mother liquors afforded 0.57 g. of yellow prisms (C), M.P. 201 C. (block). Recrystallization of (A) from petroleum naphtha (B.P. l40 C.) afforded long pale yellow needles, M.P. 198 C. (block). The X-ray patterns of these needles and the yellow prisms (C) were different. Thus, it appears that this compound can exist in dimorphic forms. Recrystallization of (B) from acetone gave yellow prisms containing a relatively small amount of yellow needles, M.P. 200 C. (block).

Elemental and infrared analyses showed that this product was 1,2-phthaloyl-4,5-dimethyl-1,2,3,6-tetrahydropyridazine, which may also be named 2,3-dimethyl-1,4-dihydropyridazino[1,2-b]phthalazine-6,1l-dione,

Analysis.Calcd for CMHMNZOZZ C, H, N, 11.56. Found: C, 69.49; H, 5.82; N, 11.48 (Dumas).

The same product was obtained by adding 1 g. of isolated, solid phthalazine-1,4-dione to a solution of excess 2,3-dimethyl-1,S-butadiene in acetone at 80 C. This gave 1.2 g. of tan solid which, on recrystallization from acetone, was obtained as bright yellow platelets, M.P. 189-195 C. (capillary).

Example VIII Treatment of an acetone-chloroform solution of phthalazine-1,4-dione, from which some precipitated material had been filtered 00?, with 1,3-butadiene at -80 C. resulted in discharge of the green color, but the adduct did not precipitate. The solution was concentrated to a small volume to obtain the adduct as white needles. The adduct was very soluble in chloroform and was recrystallized from chloroform-acetone to atford white needles, M.P. 263-268 C. with decomposition. This product was shown by elemental, infrared and n-m-r analyses to be 1,2-phthaloyl-1,2,3,6-tetrahydropyridazine,

9 also named 1,4-dihydropyridazino[1,2-b]phthalazine-6,l1- dione,

Analysis.--Calcd for C H N O C, 67.28; H, 4.71; N, 13.08. Found: C, 67.29; H, 4.96; N, 13.29 (Dumas).

Other 1,2-maleyl-1,2,3,6-tetrahydropyridazines and 1,2- phthaloyl-l,2,3,6-tetnahydropyridazines which can be obtained by following the general procedure described in the above examples, especially Example Nos. III and VIII, include the following specific compounds, among others:

1,2 maleyl 3 isopropyl-6-methyl-6-ethyl-1,2,3,6- tetrahydropyridazine, from pyridazine-3,6-dione and 2,6- dimethyl-3,5-octadiene.

Example XV 1,2-maleyl 4 (n-heptyl)-1,2,3,6-tetrahydropyridazine, from pyridazine-3,6-dione and 2-(n-hepty1)-1,3-butadiene.

Example X V1 1,2-maleyl 4 (n-decyl)-1,2,3,6-tetrahydropyridazine, from pyridazine-B,6-dione and Z-(n-decyl)-1,3-butadiene.

Example XVII 1,2-phthaloyl 3,3,6,6 tetramethyl-1,2,3,6-tetrahydropyridazine, from phthalazinel,4-dione and 1,1,4,4-tetra methyl-1,3-butadiene.

Example XVIII 1,2-ma1eyl-4-methyl 3,6 [(isopropyl)ethano]-l,2,3,6- tetrahydropyridazine, from pyridazine-3,6-dione and uphellandrene.

Example XIX 1,2 phthaloyl-3,6-ethano-1,2,3,6-tetrahydropyridazine, from phthalazine-l,4-dione and 1,3-cyclohexadiene.

Example XX In demonstration of the plant growth regulant activity possessed by the products of this invention, the following tests are described:

The foliage of three-week old xanthium, a typical noxious weed, was sprayed with 5 ml. of a composition containing 1000 parts of the compound being tested per 1,000,000 parts of solvent, which amounts to the low dosage of approximately 1 lb. of active ingredient per acre. The sprayed plants were observed after two weeks and the following comparisons were made between the treated and untreated (control) plants: plant height; fresh weight; and dry weight (after being heated to C. for about 16 hours). The following table shows that all three compounds tested have a marked growth retarding effect on the test weed. The figures shown in each column are comparisons, expressed in percent, with the untreated (control) plants the value for the latter being taken as in each case.

The compounds respectively tested were:

A. The 1,4,6,9 tetra'ketopyridazino[1,2-a]-pyridazine obtained from pyridazine-3,6-di0ne on spontaneous evolution of nitrogen (see Example I).

B. 1,2 maleyl-3,6-ethano 1,2,3,6-tetrahydropyridazine (see Example VI). I

C. 1,2 phthaloyl-l,2,3,6-tetrahydropyridazine (see Example VIII).

D. 1,2-maleyl-4,5-dimethyl-1,2,3,6-tetrahydropyridazine (see Example III). 1

. TABLE 1 Compound Plant Fresh Dry Height Weight Weight By visual observation, the plant leaves treated with A showed hormone injury and chlorosis.

Additionally, when compounds C and D were tested in the same manner on three-week old millet (a typical grass used to detect growth regulant activity), they showed growth retarding activity three weeks following? applica- While the invention has been illustrated in the foregoing examples with reference to certain specific compounds, it comprises broadly the 1,2-maleyl-1,2,3,6-tetrahydropyridazines and the 1,2-phthaloyl-1,2,3,6-tetrahydropynidazines having, respectively, the Formulas I and II set forth above, in which formulas the symbols R to R stand for hydrogen or alkyl radicals, and R and R together can form a divalent alkylene bridge. A preferred embodiment, because of the greater accessibility of the starting materials, comprises the compounds of Formulas I and II in which the groups R to R are hydrogen or alkyl radicals of 1 through 10 carbon atoms, these radicals together having a total of not more than 12 carbon atoms, and R and R when joined together, form an alkylene bridge of 1 through 5 carbon atoms. Especially preferred are the compounds in which at most two of the -R groups are alkyl radicals of 1 through 10 carbon atoms, the remaining Rs being hydrogen, and the alkylene group, when present, has either 1 or 2 carbon atoms, i.e., is methylene or ethylene.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for obvious modifications will occur to those skilled in the art.

1 1 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A compound of the formula I wherein R through R are selected from the group consisting of hydrogen and alkyl of from 1-10 carbon atoms, and R and R taken together can form an alkylene bridge of from 1-5 carbon atoms, all of R R combined having a total of up to 12 carbon atoms.

2. A compound of the formula 6 K OH 0 12 8. The process of preparing a member of the group consisting of 1,2-maleyl-1,2,3,6-tetrahydropyridazines and 1,2- phthaloyl-l,2-3,6-tetrahydropyridazines which comprises contacting in an inert liquid organic solvent at temperatures below about 0 C. a 1,3-diene hydrocarbon of the formula wherein R through R are selected from the group consisting of hydrogen and alkyl of from 1-10 carbon atoms, all of R -R combined having a total of up to 12 carbon atoms, and R and R taken together can form an alkylene bridge of from 1-5 carbon atoms, with a 2,3-diazaquinone of the formula wherein R and R are hydrogen and when taken together R, and R can form the divalent radical References (Zited in the file of this patent UNITED STATES PATENTS 2,614,916 Hoffman Oct. 21, 1952 2,640,005 Ligett et al May 26, 1953 2,759,938

Du Brevil Aug. 21, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,062,820 November 6 1962 Thomas J. Kealy It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 11 lines 17 to 26 the formula should appear as shown below instead of as in the patent:

column 11, line 35 for "[1 2-=]" read [1,2-a]

Signed and sealed this 11th day of June 1963.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

1. A COMPOUND OF THE FORMULA
 2. A COMPOUND OF THE FORMULA 